Yeast cultures are used as a source for extraction of several components. The term “yeast extract” is usually used for a concentrate of soluble material derived from yeast cells that have been subjected to hydrolysis of cell material, particularly proteins, soluble carbohydrates and nucleic acids. Yeast cells can also be used as a source for specific single components which are extracted and purified from yeast cells. These components may be naturally produced by the yeast in question or may be produced by the yeast cells after genetic manipulation. Both when producing yeast extract and when purifying specific components from yeast cell cultures there is a desire to increase the yield of the product of interest to improve the economy of the production. Production of yeast extracts is described on pages 240-251 of Nagodawithana (1995) Savory Flavours, Esteekay Associates, Inc., Wisconsin, USA.